1. Field of the Invention
This invention generally relates to a corona discharger, and more particularly to an improved corona discharger having a thin conductor as an electrode for imparting corona discharge to an opposed member to be electrically charged or discharged, and having a vibration prevention member, wherein vibration of the corona discharge wire may be prevented, whether the voltage applied to the corona discharge wire is an AC or a DC voltage which contains a pulsating component, which vibration may otherwise take place with an amplitude several hundred times as great as the diameter of such discharge wire.
2. Description of the Prior Art
FIG. 1 of the accompanying drawings schematically shows the state of vibration of a corona discharge wire 1 as observed in the corona discharger of the prior art. For example, when an AC voltage of 7 KV is applied to a gold-plated tungsten wire having a length of 450 mm and a diameter of 60 .mu., the amplitude A of vibration of the wire will reach 2 to 4 mm. Such amplitude A can be reduced by increasing the tension of the tungsten wire but cannot be nullified. Although there is another method of holding the corona discharge wire by means of a shock absorber formed of foamed polyurethane or like material to prevent the vibration of the wire, this method still permits the corona discharge wire to vibrate with the portion thereof held down by the shock absorber acting as the node. Particularly, when the frequency of the AC voltage applied is increased, the vibration tends to become stronger and the mode of the vibration may sometimes change from standing wave to traveling wave.